Copy sheet guidance device for photo-copying machines

ABSTRACT

A copying machine comprising a cylinder having a photoconductive surface on which sheets are carried, in which a movably displacable mechanical guidance device engages the leading edge of a copy sheet as it is fed to the cylinder at a first position, the guidance device remains in contact with the leading edge of the sheet as it is carried by the cylinder until the device reaches a stop where it becomes stationary and the leading edge of the copy sheet is displaced out of contact with the device for the continued onward movement of the sheet from the cylinder. The guidance device may comprise one or more anglepieces and may be controlled by a magnet and associated switch means.

[ Oct. 21, 1975 COPY SHEET GUIDANCE DEVICE FOR PHOTO-COPYING MACHINES [75] Inventor: Egon Opravil, Brackel, Germany [73] Assignee: Lumoprint Sindler KG, Hamburg,

Germany [22] Filed: Nov. 30, 1973 [21] Appl. No.: 420,580

[30] Foreign Application Priority Data 3,318,213 5/1967 Kowalski 355/14 3,380,733 4/1968 Draugelis 27l/DIG. 2 3,790,159 2/1974 Hatzmann et a1 178/7.6 X

Primary ExaminerSamuel S. Matthews Assistant Examiner-Kenneth C. I-Iutchison Attorney, Agent, or Firm-Toren, McGeady and Stanger [57] ABSTRACT A copying machine comprising a cylinder having a photo-conductive surface on which sheets are carried, in which a movably displacable mechanical guidance device engages the leading edge of a copy sheet as it is fed to the cylinder at a first position, the guidance device remains in contact with the leading edge of the sheet as it is carried by the cylinder until the device reaches a stop where it becomes stationary and the leading edge of the copy sheet is displaced out of contact with the device for the continued onward movement of the sheet from the cylinder. The guidance device may comprise one or more angle-pieces and may be controlled by a magnet and associated switch means.

20 Claims, 14 Drawing Figures US. Patent Oct. 21, 1975 Sheet 1 of 7 3,914,041

Patent Oct. 21, 1975 Sheet2of7 3,914,041

U.S. Patent Oct.21,1975 Sheet3of7 3,914,041

US. Patent Oct. 21, 1975 Sheet7 0f7 3,914,041

COPY SHEET GUIDANCE DEVICE FOR PHOTO-COPYING MACHINES FIELD OF THE INVENTION This invention relates to a sheet guidance device for use in association with a cylinder having a photoconductive surface on which sheets are carried.

Such cylinders are used in xerographically operating machines and may have a coating of selenium forming the photo-conductive surface.

BACKGROUND OF THE INVENTION In copying machines with such a cylinder, it is known to sensitize the cylinder surface by means of a corona discharge, then to illuminate the cylinder with an optical image of an original to be copied, to develop the latent electrostatic image thus created by applying developing powder to the cylinder and making the image visible, and then to guide a copy sheet, in particular a sheet of paper, on to the cylinder for the purpose of transferring the image to it, the copy paper possibly having a heat-treated surface. During the contact period when the sheet of copy paper lies on the cylinder surface and is either held there by special means or is caused to stay in contact therewith by forces of adhesion, the developed powder image is transferred to the copy sheet by the effect of a corona discharge which is polarised in known manner, i.e. by the action of an electric field. After the transfer, the copy sheet is removed from the cylinder surface and guided to a fixing device where the powder image is fixed by heating.

The present invention is applicable particularly to copying machines in which, distributed around the periphery of the cylinder in its direction of movement, are a charging device, an illumination device, the developing device with the developing powder, and the coronadischarge device which is in the region of the transfer of the powder image to the copy sheet. Such machines may include cleaning devices arranged in advance of the charging device for preparing the cylinder surface for a new copy.

If a copy sheet, which has been guided to the cylinder initially by conventional means such as feed rollers and conducting elements, with the feed rollers having the same sheet feed speed as the peripheral speed of the cylinder, is held on the cylinder by adhesion, i.e. without additional means, then under these circumstances there is the problem of removing the copy sheet from the cylinder surface at a predetermined point, for its subsequent passage to the fixing device. It is not possible for example to allow knife-like removal elements to slide against the cylinder surface, since then the cylinder surface would be damaged.

A device for removing a copy sheet from a cylinder is known from German published patent application No. 2,020,821 in which a stream of air is directed towards the removal point of the copy sheet from the cylinder surface, the air stream being directed at an angle to the direction of movement of the cylinder surface at this point in order to raise the front edge of the copy sheet after transfer thereto of the developed image and to lead the sheet to a guide member. Apart from the expense involved in providing a special blower or fan for this purpose, and especially a controllable output blower, there is also an undefinable effect, primarily because the resulting adhesive forces between the copy sheet and the cylinder surface can depend upon what percentage of the surface in the region of surface contact between the sheet and the cylinder is provided at any given time with developing powder.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a copy sheet guidance device for a cylinder having a photo-conductive surface, which device safely allows a copy sheet to be removed from the cylinder at a defined point on the periphery of the cylinder and operates without engaging into or resting upon the photoconductive surface, enables considerable speeds of operation to be achieved, imposes no limitations on the photo-conductive surface, and is simple and robust in its construction.

In accordance with the invention there is provided a sheet guidance device for a cylinder having a photoconductive surface on which sheets are carried, the device comprising mechanical guidance means arranged to be movable concentrically with respect to the cylinder and over the peripheral surface thereof, and stop means adjacent to a point on the periphery of the cylinder at which sheets carried on the cylinder are removed therefrom, said guidance means being engageable in a first position with at least one section of the leading edge of a sheet fed to the cylinder and being movable with the sheet to a second position in which the guidance means strikes said stop means, whereupon the leading edge of the sheet is freed from said guidance means.

This results in a safe, mechanical guidance device which does not co-operate directly with the surface of the cylinder.

In one preferred embodiment, the mechanical guidance means comprises an angle-piece which has a first web which is substantially tangential to the cylinder periphery and a second web which extends substantially radially of the cylinder. Such an angle-piece, whose webs can be very short, entrains the leading edge of the copy sheet and guides this edge over the periphery of the cylinder to said second position at the stop means where this edge springs out of the angle-piece due to continued onward feeding of the sheet.

Preferably, the first position for the receipt of the leading edge of a sheet is substantially at the lowest point of the cylinder, and the guidance means is arranged to be moved upwardly therefrom by the edge of the sheet as it is carried on the cylinder. After the freeing of the sheet, the angle-piece always drops back to its lower initial position, because of its weight or by using additional means. However, it is not impossible for the initial first position to be provided, in other embodiments, at other points on the periphery of the cylinder.

According to another advantageous alternative arrangement, the guidance means comprises two anglepieces positioned respectively one at each end of the cylinder and engageable with the ends of the sheet leading edge. Thus, it is sufficient for just the leading corners of the copy sheet to be retained, without a continuous retention of the sheet right along its leading edge.

Although the angle-piece or the corner angle-pieces can be guided by any suitable means concentrically of the cylinder, one advantageous embodiment provides that the angle-piece or angle-pieces are fitted on pivot arms mounted concentrically with respect to the cylinder. This provides a particularly simple but accurately defined guidance.

The mechanical guidance means may comprise an angle-piece extending the length of the cylinder and mounted on a cylinder axle by means of two pivot arms which with the angle-piece form a hoop. This is a particularly simple formation, and above all allows uniform guidance of the leading edge of the sheet over the length of the cylinder, which having regard to the adhesion forces, contributes to the achievement of uniform image transfer.

In an alternative arrangement the second web is not truly radial but extends at an angle to the radius in the direction of movement of the guidance means when engaged by a sheet and makes an obtuse angle with said first web. In connection with the supply of a sheet to the cylinder at an angle to the cylinder, and whose leading edge then moves between the webs in the region of the bisector of the web included angle, the sheet can later be removed particularly easily, since when the angle-piece is stopped by the stop means, the sheet is guided away in the peripheral direction of the cylinder.

The second web may be resilient and comprise bristles or wire pieces. The bristles or wire pieces are preferably spaced at intervals along the length of the cylin der. The flexibility thus achieved simplifies guidance of the sheet when the angle-piece is stopped, and friction between the sheet and the angle-piece at the ends of the brustles or wire pieces is limited.

Alternatively, the webs may be formed as flat pieces of material. It has been shown that the transferred powder image is not affected thereby, even if the anglepiece is held against the stop means at the removal point by the friction of the sheet passing over the anglepiece.

The guidance means preferably is at least partly of metal This has advantages in certain applications. However, in another arrangement, the guidance means can be of plastics material, particularly when using a discharge device for transferring the powder image.

The friction mentioned above when the webs are made of flat sheet material can be reduced if at least one web has bead-like projections adjacent to its free ends.

Preferably, the stop means is formed by a free end of a sheet-conducting surface which guides off-coming sheets to a pair of transport rollers. The exact removal point of the sheets from the cylinder is thus defined directly by sheet guide means.

Preferably, the sheet guidance device includes sheet supply means adjacent to said first position comprising at least one pair of transport rollers and a pair of spaced guide elements forming a supply passage therethrough, wherein the guide elements are inclined to the cylinder periphery and the ends of the guide elements facing the cylinder form abutments for the guidance means which resiliently closes said supply passage between the guide elements in its said first position. The leading edge of the sheet is thus always introduced safely to the guidance means.

The pivot arms may be biased by spring means which become stressed as said guidance means moves from said first position to said second position. This allows the mechanical guidance means to return quickly to its initial position in order to receive a new sheet. This use of springs may be extended to an arrangement in which the guidance means does not start its movement from the lowest point of the cylinder but from some other point on the cylinder periphery.

In order in particular to lessen contact between the sheet and the guidance means after the freeing of the leading edge of the sheet, one particular preferred arrangement includes a releasable retaining device for the guidance means at said second position, the retaining device being controlled by switch means which is actuated by a sheet and which is released after the trailing edge of the sheet has been removed from the cylinder. Preferably, the guidance means is at least partly metallic, and the retaining device comprises a magnet. In this connection, there is the possibility of lifting the sheet away from the guidance means, particularly when its leading edge has been freed, and possibly of guiding it past the guidance means over a spiked roller associated with the subsequent sheet-conducting element.

BRIEF DESCRIPTION OF THE DRAWINGS A number of embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

FIG. 1 is a partial side view of part of a copying machine with the elements arranged around a cylinder with a photo-conductive surface;

FIGS. 2 to 4 are views of a part of FIG. 1 with the cylinder and the angular position of a mechanical guidance device in different operational settings;

FIG. 5 is a partial side view corresponding to FIG. 4 but with additional components;

FIG. 6 is a partial side view corresponding to FIG. 4 but of a different embodiment;

FIG. 7 is a view of the elements of FIG. 6, viewed from the right, to illustrate this particular embodiment more clearly;

FIG. 8 is a partial side view on an enlarged scale of a further embodiment in accordance with the invention;

FIG. 9 is a partial view of FIG. 8, viewed from the right;

FIG. 10 is a schematic side view of the copying machine shown only partially in FIG. 1, wherein only those elements which are essential to the production of copies are shown;

FIG. 11 is a front, partial view of a cylinder and its method of mounting;

FIG. 12 is a view similar to FIG. 11 but of an alternative arrangement;

FIG. 13 is a schematic diagram of the drive means for the copying machine shown in FIG. 10; and

FIG. 14 is a perspective view of the cylinder and another embodiment of the mechanical guidance device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS plane of the drawing, one of which plates ismarked 1v in FIG. 1. An original to be copied can be moved along the top 47 of the housing 46 over a scanning slot 48, the drive for the original being effected by pairs of driven rollers 49, 50 which are reversible. In advance of and following the scanning slot 48 are switches 51, 52

which project into the path of the original and are actuated by the latter so as to trigger controls which are connected with the copying process, for example scanning light sources, charging devices, corona-discharge devices, a developing device, a cleaning device, the drive for the cylinder which is illuminated by the optical image of the original, a fixing device, and means for removing and introducing copy sheets. Such control means are known and do not need to be more fully described herein. Furthermore, it should be understood that in a known manner a carriage can alternatively be moved in a reciprocating manner over the upper surface 47. Such a carriage has a transparent surface on which the original is received.

In the following, reference is also made to FIG. 1, which shows the parts which are essential to the invention and which are illustrated as a part of a complete machine in FIG. 10.

FIG. 1 shows a section of a copying machine, where the chain-dotted lines 1 indicate the edges of plates between which the machine elements described hereinafter are positioned and on which they are mounted. Drive means can thus engage with shafts externally of a plate.

A cylinder 2 with a photo-conductive surface is mounted between the plates for rotation in the direction of arrow 3. Distributed around the periphery of the cylinder 2 are a charging device 4 with a charging wire 5 for sensitising the surface of the cylinder 2, a projecting mouth 6 of a scanning device which is not shown in more detail in FIG. 1 and by means of which an optical image of an original is projected on to the surface of the cylinder, a developing device 7, a feed or supply device 8 for copy sheets which can be of paper, plastics or the like, and a guide element 9 for leading away copy sheets into a transport device 10 and into a heating device 11 for fixing the powder image transferred to the sheet. Between the copy sheet removal point and the charging device 4 can be provided a cleaning device 12, shown for example as a belt, for the cylinder surface.

The developing device 7 comprises a supply container 13, in the lower part of which is arranged a supply of developing powder 14, from which a bucket conveyor 15 continuously supplies developing powder to a feed channel 16 which ends at the cylinder surface. After illumination, the cylinder surface is thus sprayed with developing powder in order to develop the latent image.

It is important for a further corona discharge device 17 to be provided between the copy sheet feed device 8 and the guide element 9.in order to apply an electric field of opposite polarity to that applied by the device 4 to the region where a copy sheet rests on the surface of the cylinder. The transference of the powder image is thus aided.

From FIG. 10 it can be seen that a stack 53 of copy sheets, for example sheets of paper, is arranged beneath the upper surface 47 of the housing. A withdrawal device with a delivery roller 54 acts on the uppermost sheet in order to feed such sheets in good time in known manner to a waiting position in advance of the cylinder 2 or to feed them at the correct point in the working cycle synchronised with the scanning of an original which is indicated by the switches 51, 52. A feed path 55 extends down from the withdrawal device, and several pairs of driven rollers 56 are provided along the path to transport the sheets. Beyond the last pair of rollers 56 is provided for example a trackway 45 which is upturned at its end adjacent to the cylinder 2 and which guides the sheets to a pair of transport rollers comprising rollers 18 and 19 at its upturned end.

Within the housing 46, the scanning slot 48 is illuminated by a source 57 of illumination arranged in front of a reflector. The optical image whose path 58 is indicated by a chain-dotted line is projected by two reflecting surfaces 59, 60 in a tunnel through the projecting mouth 6 of the tunnel to the surface of the cylinder 2 which is rotated while a copy is being produced. A lens 61 is located in the path 58 of the optical image.

A drive motor is provided at 62. It drives the continuously rotating parts directly and drives the parts controlled by the switches 51, 52 preferably by means of switch couplings.

The components described so far are known, but are relevant to the construction and mode of operation of the sheet guidance device according to the invention. The copy sheet feed device 8 comprises lower and upper guide elements 20 and 21 following the pair of transport rollers 18, 19 to which a copy sheet is guided from the stack 53 via the trackway 45, the guide elements 20, 21 being inclined at an angle to the lower surface of the cylinder 2 The guide element ends 22, 23 facing the cylinder 2 are spaced apart in relation to a mechanical guidance device, described hereinafter, so that the latter can close the opening of the feed path between the guide elements 20, 21.

The mechanical guidance device comprises an L- shaped angle-piece 24 which is movable above the surface of the cylinder 2 and which is mounted concentrically with respect to the cylinder axis on pivot arms 25. The cylinder 2 is for example mounted on a driven hollow shaft which has an axle 26 therethrough, at both ends of which are arranged the pivot arms 25 which carry the ends of the angle-piece 24.

In FIG..11, such a form of mounting is shown. The hollow shaft is indicated at 63. It is arranged for rotation in bearings 64 of a side plate 65 or of some other support means and carries for example a gearwheel 66 for the driving of the cylinder 2. In the hollow shaft is located the axle 26, which extends from the hollow shaft and is secured to the pivot arm 25. This rotationresisting arrangement enables separate guidance elements to be provided at the two ends of the cylinder 2, as will be described later with reference to FIG. 7 where the axle 26 is indicated at 37.

FIG. 12 shows another arrangement in which the cylinder 2 is arranged in a rotation-resisting manner on a shaft 67. This shaft 67 has its two ends guided through respective bearings 68, 69 in side plates 70, 71. On the insides of the plates 70, 71, Le. adjacent to the surfaces facing one another, the pivot arms 25, 25' are mounted so that they can swing freely by means of freelyrotatable bearing rings 72, 73 whose axial positions on the shaft 67 can be determined by collars or circlips for example. One end of the shaft 67 carries on the outside of one of the side plates 70 the gear wheel 66 for driving the cylinder 2.

The arrangement shown in FIG. 12 can be used in particular when a guidance device in the form of an angle-piece 24 is provided which extends across the full width between the free ends of the pivot arms 25, 25'.

The angle-piece is shown in FIG. 1 in its end position against an abutment 27 formed by the guide element 9,

in which position the copy sheet sweeps over the anglepiece 24 as indicated by the chain-dotted line 28 and holds the angle-piece against the abutment 27.

The transport means formed by the rollers 18, 19 is positioned at a distance from the abutment 27 which is less than the length of a copy sheet, measured along the path of movement of the copy sheet.

Several operational positions of this embodiment are shown in FIGS. 2 to 4, in which the same parts in the various views have been marked with the same reference numerals.

FIG. 2 shows the angle-piece 24 in its initial position against the copy sheet feed device 8. The angle-piece has a first web 29 which is substantially parallel to the cylinder surface and a second web 30 which is substantially radial to the cylinder. The web 29 has a width of for example 2 to 3 mm. The free ends of the webs 29, 30 rest against the ends 22, 23 of the guide elements 20, 21 in the initial position, under the weight of the guidance device. A copy sheet introduced along the chain-dotted line 44 through the pair of driven rollers 18, 19 thus passes automatically to the angle-piece 24. This sheet, as it advances, pushes the angle-piece 24 in an anticlockwise direction in turn to the positions shown in FIG. 3 and FIG.4. The sheet sticks to the surface of the cylinder by adhesion, as is shown by the path of the chain-dotted line, and care must be taken that the driving force imparted to the sheet by the pair of rollers 18, 19 is matched to the peripheral speed of the cylinder 2.

When the angle-piece 24, in particular its radial web 30, reaches the abutment 27, then the leading edge of the copy sheet springs out of the angle-piece 24 due to the sheet being pushed onwards by the pair of rollers l8, l9 and due to the adhesive force between the sheet and the cylinder 2. The sheet is then guided by the guide element 9 to the similarly driven pair of rollers and from there to the fixing device.

After the trailing edge of the copy sheet, which holds the angle-piece 24 against the abutment 27, has passed the angle-piece, the latter in one embodiment returns to its original position as shown in FIG. 2 due to its own weight.

FIG. 5 shows a modification in that a retaining electromagnet 31 for the angle-piece 24 is provided on the abutment 27. This retaining magnet 31 is made operational by a switch 32 being tripped by the leading edge of the copy sheet as it moves along the chain-dotted path 28, and the magnet remains connected in circuit until the trailing edge of the sheet releases the switch 32 again. It is also to be noted that the switch 32 can be a change-over or reversing switch, which can thus cause a contrary excitation of the magnet so as to repel the angle-piece 24 momentarily. In this embodiment, the angle-piece 24 is made of metal. If the angle-piece were made of a plastics material, the retaining magnet 31 could be positioned at 33 in the path of movement of one of the pivot arms 25 which would then be of metal.

In the embodiment of FIG. 5, special means can be arranged on the abutment 27 in relation to the radial web 30, for example in the form of a small spiked roller, in order to lead the sheet over and past the radial web 30 without contact therewith after it has once come free from the angle-piece 24.

FIG. 5 shows a further feature in that springs 38 engage on the axle 26 of the hoop comprising the anglepiece 24 and pivot arms 25, 25, these being for example in the form of helical springs which become stressed by the movement of the angle-piece 24 toward the abutment 27 and thus accelerate the return of the angle-piece after its release.

correspondingly, there is the possibility of providing a return spring in the magnet 31 in this construction, in order to thrust away and to accelerate the angle-piece 24 into its return movement after de-energisation of the magnet.

FIGS. 6 and 7 show the use only of corner anglepieces 34, 35, each being mounted on a respective pivot arm 25, 36. The two pivot arms 25 36 are however arranged on a common axle 37 which passes through the hollow shaft of the cylinder 2. FIG. 6 shows that the corner angle-pieces 34, 35 can be shaped in the same way as the elongate angle-piece 24. The construction shown in FIGS. 6 and 7 has the advantage that the copy sheet can have an image made on it right up to its leading edge.

FIGS. 8 and 9 show a further variation in which instead of having a radial second web 30, the corresponding part 39 of the angle-piece makes an obtuse angle with the tangential web 29. From this, it can be seen that the copy sheet can slide or spring out of the anglepiece more easily when it reaches the abutment 27 The guidance of the copy sheet along the chain-dotted path 28 can be improved by arranging bead-like projections 40, 41 42, 43 near to the free ends of the anglepiece webs 29, 39.

According to another alternative arrangement, as shown in FIG. 4 the outwardly projecting web 30 or 39 consists of bristles or resilient pieces of wire B arranged at spaced intervals along the first web A at distances corresponding approximately to those between the bead-like projections 42 and 43 of FIG. 9.

FIG. 13 is a schematic diagram showing the drive means for the machine. A motor 62 and associated switch 77 on the one hand and a switch-relay assembly indicated generally at 78 and associated switches 51 and 52 on the other hand are connected between supply rails and 76. The motor 62 drives transmission gearing 79, to which are directly coupled the pairs of rollers 49, 50 and 56, the further pairs of rollers arranged in the feed path 55, the pair of rollers 10, and the further pairs of rollers arranged in the fixing device 11. Furthermore, the gearing 79 drives a clutch device 80 which is controlled by the switch-relay assembly 78 and which drives the cylinder 2, the withdrawal roller 54, the pair of transport rollers 18, 19, the cleaning device 12, and the developing device 7 by way of gearing 81. The switch-relay assembly 78 also connects into circuit the source of illumination 57, the charging device 4, the corona discharge device 17, and the heating device 11, in dependence on the actuation of the switches 51, 52. Suitable delay elements can be provided for the individual switching means to ensure the necessary duration of their connection in circuit.

- carrying the leading edge of a copy sheet as the copy sheet moves in an arcuate path in contact with said cylinder from a first position where it moves into contact with the photo-conductive surface of said cylinder to a second position where it moves out of contact with the photo-conductive surface, said device comprising mechanical guidance means arranged to be movably displaced from the first position to the second position concentrically with respect to the central axis of said cylinder, said mechanical guidance means includes a support member for the leading edge of the copy sheet located adjacent to and spaced outwardly from the circumferential peripheral surface of said cylinder, stop means positioned adjacent to and radially outwardly from the circumferential periphery of said cylinder at the second position where the copy sheet is removed from said cylinder, and transport means for moving a copy sheet and said guidance means from the first position to the second position, said support member of said guidance means being engageable in the first position by the leading end of a copy sheet and being movable by the leading edge of the copy sheet via said transport means for displacing said guidance means to the second position in which said support member strikes said stop means, whereupon the leading edge of the copy sheet is deflected outwardly from said support member and is driven from said cylinder.

2. In a copying machine including a cylinder arranged to be rotated about its central axis and having a continuous circumferentially extending photoconductive surface spaced radially outward from its central axis onto which surface an optical image can be transferred, first transport means for feeding individual copy sheets into contact with the photo-conductive surface of said cylinder so that the image can be transferred from the cylinder to the copy sheet, second transport means for receiving individual copy sheets from said cylinder and spaced angularly about said cylinder from said first transport means, means arranged to contact the leading end of a copy sheet for guiding it as the copy sheet travels in contact with said cylinder from said first transport means to said second transport means and for lifting the copy sheet off the cylinder as the leading end of the copy sheet reaches the second transport means, said means for guiding and lifting the copy sheet comprising support members pivotally displaceable about the central axis of said cylinder and extending'radially from the central axis and having free ends at the radially outer ends thereof, and a copy sheet leading edge guide device secured to the free ends of said support members and positioned radially outwardly from and adjacent to the circumferentially extending surface of said cylinder, said support members being freely movable about the central axis of said cylinder between said first and second transport means, said first transport means including a stop for limiting the movement of said guide device in the direction from said second transport means toward said first transport means, said second transport means including a stop located in the path of said guide device for blocking its path of movement about the cylinder, said first transport means feeding the copy sheets so that the leading edge of each copy sheet as it is fed to the cylinder contacts said guide device at the stop of the said first transport means and the leading edge of the copy sheet displaces said guide device about the circumferential surface of said cylinder until said guide device contacts said stop of said second transport means whereupon the continued feeding action on the copy sheet causes its leading edge to deflect outwardly from the circumferential surface of said cylinder for entry into said second transport means.

3. A machine according to claim 2, in which the means for guiding and lifting is made at least partly of metal.

4. A machine according to claim 2, in which the means for guiding and lifting is made at least partly of plastics material.

5. A machine according to claim 2, in which the stop of said second transport means is formed by a free end of a sheet-conducting surface which guides off-coming sheets to a pair of transport rollers.

6. A machine according to claim 2, wherein said guide device comprises an L-shaped angle-piece having a first web which is substantially tangential to the circumferential periphery of the cylinder and a second web which extends radially of the central axis of the cylinder.

7. A machine according to claim 6, wherein said support members are pivot arms and the opposite ends of said angle-piece are fitted to said pivot arms and travel in an arc mounted concentrically with respect to the central axis of said cylinder.

8. A machine according to claim 7, including spring means biasing said pivot arms so that said spring means become stressed as said means for guiding and lifting move toward said stop on said second transport means.

9. A machine according to claim 6, in which the webs are formed as thin planar flat pieces of material.

10. A machine according to claim 6, in which beadlike projections are provided adjacent to the free ends of at least one web.

1 l. A machine according to claim 2, wherein the central axis of said cylinder is horizontal and the stop of said first transport means at which the sheet is directed into contact with said cylinder is substantially at the lowest point of the cylinder, and said guide device is arranged to be moved upwardly therefrom by the leading edge of the sheet as it is carried on the cylinder.

12. A machine according to claim 2, wherein said guide device comprises two L-shaped angle-pieces positioned respectively one at each end of the cylinder and engageable with the opposite ends of the copy sheet leading edge.

13. A machine according to claim 12, wherein said support members are pivot arms and said angle-pieces are each fitted to a different one of said pivot arms and travel in an are mounted concentrically with respect to the central axis of said cylinder.

14. A machine according to claim 2, wherein said cylinder includes a cylinder axle coaxial with its central axis, said support members are pivot arms freely pivotally mounted each at an opposite end of said cylinder axle, and said guide device comprises an angle-piece extending for the axial length of the cylinder and mounted on the ends of said pivot arms spaced radially outwardly from said cylinder axle so that said cylinder axle, said pivot axis and said angle-piece form a hoop.

15. A machine according to claim 2, wherein said guidedevice comprises an angle-piece having a first web which is substantially tangential to the circumferential periphery of said cylinder and a second web which extends outwardly from said first web away from said cylinder and forms an obtuse angle with said first web.

16. A machine according to claim 15, in which said second web is resilient and comprises bristles.

17. A machine according to claim 16 in which said bristles are spaced at intervals along said second web along the length of the cylinder.

18. A machine according to claim 2, wherein said first transport means includes sheet supply means adjacent to said cylinder and comprising at least one pair of transport rollers and a pair of spaced guide elements forming a supply passage therebetween, wherein the guide elements are inclined to the circumferential periphery of said cylinder and the ends of the guide elements facing the cylinder form said stop of said first transport means for said guide device which closes the supply passage between said guide elements when said guide device contacts said stop.

19. A machine according to claim 2, including a releasable retaining device located adjacent to the position of said means for guiding and for lifting the copy sheet when its movement is blocked by said stop on said second transport means and said retaining device arranged for releasably holding said means in the blocked position, and switch means operatively associated with said retaining device and located in the path of a copy sheet as the copy sheet moves from said first transport means to said second transport means so that said switch means actuates said retaining device as the leading end of the copy sheet passes the switch means for effecting the holding action on said means and for releasing the holding action on said means when the V 'UNI'IICI.) S'IA'IES PA'll'lN'l (j m: (IICR'IIFICATE OF CORREC'llON Patent No. 391 10 11 I Dated October 21 1975 lnventofls). FTOT] Ooravil It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading of the oatent [73] should read as follows:

-[73] Lumonrint Zindler KG.

Signed and Scaled this thirteenth Day of April 1976 [SEAL] Affesf.

RUTH C. MASON C. MARSHALL DANN Anesting Officer Commissioner uj'lau'ms and Trademarks I UNl'llll) S'IA'IES PATEN'I (I .t"l(ll'l (IER'IIE ICATE 01* CORKECllUN Patent No. 391 10 11 Dated October 21, 1975 Inventor(s)- Err-On I' PElVll It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the headin of the oatent [73] should read as follows:

-[73] Lumonrint Zindler KG.

Signed and Salad this thirteenth D 3y Of April 1976 [SEAL] A ltest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (mnmissiunvr Q/PHIL'IIIS and Trademarks 

1. A copying machine including a cylinder mounted for rotation about its central axis and having a continuous circumferentially extending photo-conductive surface spaced radially outward from its central axis onto which surface an optical image can be transferred, a copy sheet guiding device arranged for supporting and carrying the leading edge of a copy sheet as the copy sheet moves in an arcuate path in contact with said cylinder from a first position where it moves into contact with the photoconductive surface of said cylinder to a second position where it moves out of contact with the photo-conductive surface, said device comprising mechanical guidance means arranged to be movably displaced from the first position to the second position concentrically with respect to the central axis of said cylinder, said mechanical guidance means includes a support member for the leading edge of the copy sheet located adjacent to and spaced outwardly from the circumferential peripheral surface of said cylinder, stop means positioned adjacent to and radially outwardly from the circumferential periphery of said cylinder at the second position where the copy sheet is removed from said cylinder, and transport means for moving a copy sheet and said guidance means from the first position to the second position, said support member of said guidance means being engageable in the first position by the leading end of a copy sheet and being movable by the leading edge of the copy sheet via said transport means for displacing said guidance means to the second position in which said support member strikes said stop means, whereupon the leading edge of the copy sheet is deflected outwardly from said support member and is driven from said cylinder.
 2. In a copying machine including a cylinder arranged to be rotated about its central axis and having a continuous circumferentially extending photo-conductive surface spaced radially outward from its central axis onto which surface an optical image can be transferred, first transport means for feeding individual copy sheets into contact with the photo-conductive surface of said cylinder so that the image can be transferred from the cylinder to the copy sheet, second transport means for receiving individual copy sheets from said cylinder and spaced angularly about said cylinder from said first transport means, means arranged to contact the leading end of a copy sheet for guiding it as the copy sheet travels in contact with said cylinder from said first transport means to said second transport means and for lifting the copy sheet off the cylinder as the leading end of the copy sheet reaches the second transport means, said means for guiding and lifting the copy sheet comprising support members pivotally displaceable about the central axis of said cylinder and extending radially from the central axis and having free ends at the radially outer ends thereof, and a copy sheet leading edge guide device secured to the free ends of said support members and positioned radially outwardly from and adjacent to the circumferentially extending surface of said cylinder, said support members being freely movable about the central axis of said cylinder between said first and second transport means, said first transport means including a stop for limiting the movement of said guide device in the direction from said second transport means toward said first transport means, said second transport means including a stop located in the path of said guide device for blocking its path of movement about the cylinder, said first transport means feeding the copy sheets so that the leading edge of each copy sheet as it is fed to the cylinder contacts said guide device at the stop of the said first transport means and the leading edge of the copy sheet displaces said guide device about the circumferential surface of said cylinder until said guide device contacts said stop of said second transport means whereupon the continued feeding action on the copy sheet causes its leading edge to deflect outwardly from the circumferential sUrface of said cylinder for entry into said second transport means.
 3. A machine according to claim 2, in which the means for guiding and lifting is made at least partly of metal.
 4. A machine according to claim 2, in which the means for guiding and lifting is made at least partly of plastics material.
 5. A machine according to claim 2, in which the stop of said second transport means is formed by a free end of a sheet-conducting surface which guides off-coming sheets to a pair of transport rollers.
 6. A machine according to claim 2, wherein said guide device comprises an L-shaped angle-piece having a first web which is substantially tangential to the circumferential periphery of the cylinder and a second web which extends radially of the central axis of the cylinder.
 7. A machine according to claim 6, wherein said support members are pivot arms and the opposite ends of said angle-piece are fitted to said pivot arms and travel in an arc mounted concentrically with respect to the central axis of said cylinder.
 8. A machine according to claim 7, including spring means biasing said pivot arms so that said spring means become stressed as said means for guiding and lifting move toward said stop on said second transport means.
 9. A machine according to claim 6, in which the webs are formed as thin planar flat pieces of material.
 10. A machine according to claim 6, in which bead-like projections are provided adjacent to the free ends of at least one web.
 11. A machine according to claim 2, wherein the central axis of said cylinder is horizontal and the stop of said first transport means at which the sheet is directed into contact with said cylinder is substantially at the lowest point of the cylinder, and said guide device is arranged to be moved upwardly therefrom by the leading edge of the sheet as it is carried on the cylinder.
 12. A machine according to claim 2, wherein said guide device comprises two L-shaped angle-pieces positioned respectively one at each end of the cylinder and engageable with the opposite ends of the copy sheet leading edge.
 13. A machine according to claim 12, wherein said support members are pivot arms and said angle-pieces are each fitted to a different one of said pivot arms and travel in an arc mounted concentrically with respect to the central axis of said cylinder.
 14. A machine according to claim 2, wherein said cylinder includes a cylinder axle coaxial with its central axis, said support members are pivot arms freely pivotally mounted each at an opposite end of said cylinder axle, and said guide device comprises an angle-piece extending for the axial length of the cylinder and mounted on the ends of said pivot arms spaced radially outwardly from said cylinder axle so that said cylinder axle, said pivot axis and said angle-piece form a hoop.
 15. A machine according to claim 2, wherein said guide device comprises an angle-piece having a first web which is substantially tangential to the circumferential periphery of said cylinder and a second web which extends outwardly from said first web away from said cylinder and forms an obtuse angle with said first web.
 16. A machine according to claim 15, in which said second web is resilient and comprises bristles.
 17. A machine according to claim 16 in which said bristles are spaced at intervals along said second web along the length of the cylinder.
 18. A machine according to claim 2, wherein said first transport means includes sheet supply means adjacent to said cylinder and comprising at least one pair of transport rollers and a pair of spaced guide elements forming a supply passage therebetween, wherein the guide elements are inclined to the circumferential periphery of said cylinder and the ends of the guide elements facing the cylinder form said stop of said first transport means for said guide device which closes the supply passage between said guide elements when said guide device contacts said stop.
 19. A machine according to claim 2, including a releasable retaining device located adjacent to the position of said means for guiding and for lifting the copy sheet when its movement is blocked by said stop on said second transport means and said retaining device arranged for releasably holding said means in the blocked position, and switch means operatively associated with said retaining device and located in the path of a copy sheet as the copy sheet moves from said first transport means to said second transport means so that said switch means actuates said retaining device as the leading end of the copy sheet passes the switch means for effecting the holding action on said means and for releasing the holding action on said means when the trailing end of the copy sheet passes the switch.
 20. A machine according to claim 19, wherein said means for guiding and for lifting is at least partly metallic, and said retaining device comprises a magnet for releasably holding the metallic part of said means for guiding and for lifting. 